Prior art automatic power transmissions generally include control apparatus having a hydraulic power source in valve mechanisms for controlling a plurality of friction devices that are applied by hydraulic power to associated pistons. While these control apparatus work quite well and have been very successful over the years, they do require the addition of mechanisms within the power transmission that require space and also induce a degree of temperature rise to the operation of the power transmission. While all of the fluid mechanisms of the power transmission may not be eliminated, the fluid passages, except for lubrication passages, within the main mechanical components of the power transmission can be eliminated.
The fluid-operated devices of power transmission controls can be supplanted with torque-to-thrust mechanisms such as those shown in U.S. Ser. No. 10/303,245 filed Nov. 25, 2002; U.S. Ser. No. 10/319,957 filed Dec. 16, 2002; and U.S. Ser. No. 10/946,759, filed Sep. 22, 2004, all of which are assigned to the assignee of the present application.